Masterless control system methods for networked water heaters

Abstract

Disclosed is a masterless control system for controlling a plurality of fluidly and operably connected water heaters to meet a hot water demand such that overall efficiency is maximized and usage disparity between water heaters is minimized. There is further disclosed a method for detecting a small system demand in said network by adjusting the setting of each flow limiting valve of each water heater. There is still further disclosed a method for enabling seamless addition or removal of a heater in service and heating load distribution to water heaters.

Description

PRIORITY CLAIM AND RELATED APPLICATIONS[0001]This continuation-in-part application claims the benefit of priority from provisional application U.S. Ser. No. 61 / 149,418 filed Feb. 3, 2009 and non-provisional application U.S. Ser. No. 12 / 699,487 filed Feb. 3, 2010. Each of these applications is incorporated by reference in its entirety.BACKGROUND OF THE INVENTION[0002]1. The Field of the Invention[0003]The present invention relates generally to the control of heating devices, and more specifically, to a masterless control scheme of a network of fluidly and functionally connected water heaters.[0004]2. Background Art[0005]The art of using water heaters in cascaded fashion to meet large water heating loads is not new. In a cascade system, a plurality of water heaters is used to participate in sharing water heating load to meet a demand. Typically, in a large commercial building, apartment complex, hotel or laundromat, the demand for hot water can range from zero to a very large demand i...

AI Technical Summary

Benefits of technology

[0015]It is another object of the present invention to provide a cascade water heater control system that maximizes thermal efficiency while minimizing disparity in wear across all water heaters in the system.

[0016]It is another object of the present invention to provide a cascade water heater control system that minimizes operating cost while minimizing disparity in wear across all water heaters in the system.

[0017]It is yet another object of the present invention to provide a cascade water heater control system that is plug and play, i.e., without having to use a master controller to configure or reconfigure the make-up of a network before the network can start or continue functioning.

Problems solved by technology

A single commercial or residential hot water heater is incapable of providing such a wide ranging demand in real time.

Another drawback of using a single unit under such circumstance is that it provides a single point of failure.

Other drawbacks of using a single water heater include the excessive physical size and inefficient heating associated with excessive physical size.

Furthermore, a cascaded system involving multiple water heaters affords failure redundancy not available in a single water heater system.

As such, the last water heater turned on may experience excessive cycling on and off if a requested demand falls within a dead band.

This zone, which may be referred to as a dead band or dead zone, presents unique operational problems because the next adjacent boiler cannot modulate within that range.

While heater cycling is minimized, Paine falls short of addressing the issue of distributing flow to conserve energy.

In conventional cascade water heater systems, there often exists a significant disparity in usage between water heaters in a network.

Water heaters experiencing higher accumulated usage require more regular preventative or unscheduled maintenance while others are underutilized.

The practice of using operating hours alone as a measure to estimate a water heater's remaining life is fraught with uncertainties since there are other significant factors affecting the water heater's remaining life.

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